This PDF file contains the front matter associated with SPIE Proceedings Volume 6686, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

In a joint program of Penn State University and Teledyne Imaging Sensors, hybrid CMOS sensors have been developed for use as X-ray detectors. This detector technology can provide major improvements in performance relative to CCDs, which are the current standard technology used in the focal planes of X-ray telescopes (e.g. Chandra, XMM, Suzaku, and Swift). Future X-ray telescope missions are all likely to have significantly increased collection area. If standard CCDs are used, the effects of saturation (pile-up) will have a major impact, while radiation damage will impact the quality and lifetime of the detectors. By reading out the hybrid CMOS detector in a pixel-by-pixel fashion at high speeds, with an energy resolution similar to CCDs, CMOS sensors could increase the range of pile-up free operation by several orders of magnitude. They are also several orders of magnitude more radiation hard than typical CCDs since they transfer charge through the thickness of the device, rather than across the length of its surface. Furthermore, hybrid CMOS detectors can be programmed to read out any variety of windowed regions, which leads to versatility and speed. All of this can be achieved, in principle, while maintaining the same quantum efficiencies achievable in CCDs. Results of this development effort and preliminary tests of fabricated detectors will be presented, along with potential applications for future missions such as EDGE and Constellation-X.

Soon after the start of science operations of the Chandra X-ray Observatory, it became apparent that weakly penetrating (0.1-0.5 MeV) protons in the Earth's radiation belt were causing an unexpectedly rapid increase in the charge-transfer inefficiency of Chandra's front-illuminated CCDs. Fortunately, the Chandra team developed, implemented, and maintains a radiation-protection program that successfully reduced the rate of degradation of the CCDs' performance to acceptable levels. Since implementing this program, the average rate of increase of the charge-transfer inefficiency has slowed to 3.2×10^-6/y (2.3%/y) for the front-illuminated CCDs and 1.0×10^-6/y (5.8%/y) for the back-illuminated CCDs. This paper reviews the Chandra radiation-management program, reports the current status, and describes changes planned or implemented since the previous paper on this topic.

The Extreme-Ultraviolet Variability Experiment (EVE) is a component of NASA's Solar Dynamics Observatory (SDO) satellite, aimed at measuring the solar extreme ultraviolet (EUV) irradiance with high spectral resolution, temporal cadence, accuracy, and precision. The required high EUV quantum efficiency (QE), coupled with the radiation dose to be experienced by the detectors during the five year mission (~1 Mrad), posed a serious challenge to the charge-coupled device (CCD) detectors. MIT Lincoln Laboratory developed the 2048 × 1024 pixel CCDs and integrated them into the detector system. The devices were back-side thinned and then back surface passivated using a thin, heavily boron-doped silicon layer grown by molecular beam epitaxy (MBE) at less than 450°C. Radiation-hardness testing was performed using the Brookhaven National Laboratory's National Synchrotron Light Source (BNL/NSLS). The MBE-passivated devices were compared against devices with back surfaces passivated with a silver charge chemisorption process and an ion-implant/furnace anneal process. The MBE devices provided both the highest QE at the required (-100°C) operating temperatures, and superior radiation hardness, exceeding the goals for the project. Several flight-ready devices were delivered with the detector system for integration with the satellite.

We report the most recent work of our group of the development of avalanche photo diodes based on (Al)GaN. The goal of this group is to achieve single photon counting. In this paper we first give the scientific motivation for making such a device in the context of UV astronomy and then describe current work and plans for future development. The development includes improving the sensitivity to be able to carry out single photon detection and the fabrication of arrays.

Individual x-ray calorimeters based on superconducting transition-edge sensors (TES) have already demonstrated the spectral resolution, speed, and quantum efficiency needed for astrophysical x-ray spectroscopy. We are now beginning to realize this capability on the array scale for the first time. We have developed a new design for the x-ray absorber that has connections to the TES engineered to allow contact only in regions that do not serve as the active thermometer. We have further constrained the design so that a low-resistance absorber will not electrically short the TES, permitting the use of high-conductivity electroplated gold for the x-ray absorber. With such a well-behaved material for the absorber, we now achieve energy resolution at 6 keV in the range 2.4 - 3.1 eV FWHM in all the pixels of the same design tested in a close-packed array. We have achieved somewhat higher resolution and faster response by eliminating some of the gold and electroplating bismuth in its place. These are important steps towards the high-resolution, high-fill-factor, microcalorimeter arrays needed for x-ray astrophysics observatories such as Constellation-X.

We present science highlights and performance from the Swift X-ray Telescope (XRT), which was launched on November 20, 2004. The XRT covers the 0.2-10 keV band, and spends most of its time observing gamma-ray burst (GRB) afterglows, though it has also performed observations of many other objects. By mid-August 2007, the XRT had observed over 220 GRB afterglows, detecting about 96% of them. The XRT positions enable followup ground-based optical observations, with roughly 60% of the afterglows detected at optical or near IR wavelengths. Redshifts are measured for 33% of X-ray afterglows. Science highlights include the discovery of flaring behavior at quite late times, with implications for GRB central engines; localization of short GRBs, leading to observational support for compact merger progenitors for this class of bursts; a mysterious plateau phase to GRB afterglows; as well as many other interesting observations such as X-ray emission from comets, novae, galactic transients, and other objects.

The Swift X-ray Telescope (XRT) is a CCD based X-ray telescope designed for localization, spectroscopy and long term light curve monitoring of Gamma-Ray Bursts and their X-ray afterglows. Since the launch of Swift in November 2004, the XRT has undergone significant evolution in the way it is operated. Shortly after launch there was a failure of the CCD thermo-electric cooling system, which led to the XRT team being required to devise a method of keeping the CCD temperature below −50C utilizing only passive cooling by minimizing the exposure of the XRT radiator to the Earth. We present in this paper an update on how the modeling of this passive cooling method has improved in first ~1000 days since the method was devised, and the success rate of this method in day-to-day planning. We also discuss the changes to the operational modes and onboard software of the XRT. These changes include improved rapid data product generation in order to improve speed of rapid Gamma-Ray Burst response and localization to the community; changes to the way XRT observation modes are chosen in order to better fine tune data acquisition to a particular science goal; reduction of "mode switching" caused by the contamination of the CCD by Earth light or high temperature effects.

The X-ray telescope (XRT) on board the Swift Gamma Ray Burst Explorer has successfully operated since the spacecraft launch on 20 November 2004, automatically locating GRB afterglows, measuring their spectra and lightcurves and performing observations of high-energy sources. In this work we investigate the properties of the instrumental background, focusing on its dynamic behavior on both long and short timescales. The operational temperature of the CCD is the main factor that influences the XRT background level. After the failure of the Swift active on-board temperature control system, the XRT detector now operates at a temperature range between -75C and -45C thanks to a passive cooling Heat Rejection System. We report on the long-term effects on the background caused by radiation, consisting mainly of proton irradiation in Swift's low Earth orbit and on the short-term effects of transits through the South Atlantic Anomaly (SAA), which expose the detector to periods of intense proton flux. We have determined the fraction of the detector background that is due to the internal, instrumental background and the part that is due to unresolved astrophysical sources (the cosmic X-ray background) by investigating the degree of vignetting of the measured background and comparing it to the expected value from calibration data.

The Swift X-ray Telescope focal plane camera is a front-illuminated MOS CCD, providing a spectral response kernel of 135 eV FWHM at 5.9 keV as measured before launch. We describe the CCD calibration program based on celestial and on-board calibration sources, relevant in-flight experiences, and developments in the CCD response model. We illustrate how the revised response model describes the calibration sources well. Comparison of observed spectra with models folded through the instrument response produces negative residuals around and below the Oxygen edge. We discuss several possible causes for such residuals. Traps created by proton damage on the CCD increase the charge transfer inefficiency (CTI) over time. We describe the evolution of the CTI since the launch and its effect on the CCD spectral resolution and the gain.

The Constellation-X mission will address questions central to the NASA Beyond Einstein Program, using high throughput X-ray spectroscopy to measure the effects of strong gravity close to the event horizon of black holes, study the formation and evolution of clusters of galaxies to precisely determine cosmological parameter values, measure the properties of the Warm-Hot Intergalactic Medium, and determine the equation of state of neutron stars. Achieving these science goals requires a factor of ~100 increase in sensitivity for high resolution spectroscopy over current X-ray observatories. This paper briefly describes the Constellation-X mission, summarizes its basic performance parameters such as effective area and spectral resolution, and gives a general update on the mission. The details of the updated mission configuration, compatible with a single Atlas-V 551 launch vehicle, are presented.

The hard X-ray sky has tremendous potential for future discoveries and is one of the last electromagnetic regimes without a sensitive all-sky survey. A new approach to such a survey is to utilize the Moon as an occulting disk. The Lunar Occultation Observer (LOCO) mission concept, based on this Lunar Occultation Technique (LOT) and incorporating advanced inorganic scintillators as a detection medium, represents a sensitive and cost effective option for NASA's Beyond Einstein Black Hole Finder Probe or a future Explorer-class mission. We present the motivating factors for the LOT, outline developmental details and simulation results, as well as give preliminary estimates for source detection sensitivity.

SIMBOL-X is a space-based X-ray telescope operating from 0.5 keV up to 80 keV providing an improvement of roughly two orders of magnitude in sensitivity and angular resolution compared to the instruments that have operated so far above 15 keV. This breakthrough is reached thanks to the use of Wolter-I optics based on shells working in grazing incidence combined with a large focal length (20 meters). With these characteristics, the size and the mass of a classical monolithic instrument would be well beyond the capacity of the most powerful launchers. For that reason SIMBOL-X is the first operational mission relying on two satellites flying in formation. The so-called mirror satellite carries the mirror of the telescope, while the detector satellite drives the detector assembly. The first one moves freely on a high elliptical orbit controlling its attitude towards the target, while the latter controls its 3- axis position and attitude so as to keep the detector assembly right at the mirror focal point and perpendicular to its axis. This promising concept of formation flight raises a variety of problematics, such as relative navigation, communications, operations, safety, simulation and performance evaluation. After a successful concept study, the current feasibility phase provides answers to each of these issues. The SIMBOL-X project is a cooperation between the French Space Agency (CNES) and the Italian Space Agency (ASI). The design of the instrument involves a number of laboratories in France (CEA, CESR, APC), in Italy (INAF, IASF) and in Germany (MPE, IAAT, TUD).

A pnCCD detector fulfils all typical requirement specifications to an X-ray detector optimally: The energy of the X-ray photon is precisely measured, incidence position is determined even more accurate than the pixel size, and the arrival time of the photon is very well defined by the high frame rate due to complete parallel signal processing. The probability for detection of an X-ray photon is from 0.3 keV to 10 keV close to 100% and homogeneous over the image area. Such a detector has been developed for application in X-ray astronomy. The XMM-Newton space observatory is already equipped with a pnCCD camera which performs since commissioning in 2000 till this day excellent measurements. For the upcoming eROSITA telescope on the Spectrum-Roentgen-Gamma satellite, an advanced pnCCD detector system is presently developed. Seven pnCCD cameras are placed in the foci of seven X-ray mirror systems researching the X-ray sky during a mission time of 5 years. For ground based instrumentation the X-ray fluxes can be extremely high, as it is the case in X-ray free electron lasers (XFELs). The evolving XFELs will make it possible to capture three-dimensional images of the nanocosmos. Here the focus is set on the measurement of X-ray intensities instead of spectroscopy, i.e. the number of monochromatic photons per pixel (up to > 1000 photons) is counted at very high frame rates ( > 100/s). Both projects have again in common the request for large image areas: in case of eROSITA seven times an image area of 8 cm² and for the XFEL experiment at LCLS we provide in a first step a 59 cm² large image area. In a second step it will be enlarged to even 236 cm². We performed recently promising tests with the prototype detectors. Therefore we started the production of the final devices for both applications in the MPI semiconductor laboratory.

The Indian Space Research Organisation (ISRO) Chandrayaan-1 mission is India's first lunar spacecraft, containing a suite of instruments to carry out high-resolution remote sensing of the Moon at visible, near infrared and X-ray wavelengths. Due for launch in early 2008, the spacecraft will carry out its two year mission in a polar orbit around the Moon at an altitude of 100 km. One of the eleven instruments in the spacecraft payload is the Chandrayaan-1 X-ray Spectrometer (C1XS), a descendant of the successful D-CIXS instrument that flew on the European Space Agency SMART-1 lunar mission launched in 2003. C1XS consists of 24 swept-charge device (SCD) silicon X-ray detectors arranged in 6 modules that will carry out high quality X-ray spectroscopic mapping of the Moon using the technique of X-ray fluorescence. This paper presents an overview of the Chandrayaan-1 mission and specifically the C1XS instrument and describes the development of an SCD test facility, proton irradiation characterisation and screening of candidate SCD devices for the mission.

The European Space Agency (ESA) X-ray Evolving Universe Spectroscopy (XEUS) mission is designed as a follow-on to the ESA X-ray Multi Mirror (XMM-Newton) mission and may contain charge-coupled device (CCD) based instrumentation. Low instrument background is essential for the mission to maximise sensitivity. Results from XMM-Newton and the Japanese Space Agency Suzaku mission show that both the detector design and the orbit (LEO vs. HEO) have major impacts on the instrument background. This gives implications for the optimal instrument configuration for XEUS and other future missions. Here we use a Monte Carlo simulation technique, utilising the Geant4 toolkit, to model the instrument background for CCDs in-orbit. The model will be initially verified by simulating the background from the XMM-Newton and Suzaku missions and comparing this to real data obtained in-orbit. The simulated data will then be analysed to gain a better understanding of the cause of the background. Suggestions for minimizing the instrument background in future missions based on the results found here are included.

We propose a gamma-ray burst detector (GRB) detector combining the silicon drift detector (SDD) array and scintillators with broadband X-ray and gamma-ray coverage (0.5-1000 keV or more), high energy resolution (2-10%) and high time resolution (~μs) in space. To realize such compact high-performance detector without photomultiplier tubes, we constructed proto-type model using KETEK SDD with a detection area of 1 cm² and BGO crystal. Signals from both detectors are clearly separated by the double integration method. The detector shows a very good performance. Obtained FWHM energy resolution was 191 eV at 5.9 keV in the SDD, while 6.5% at 662 keV in the BGO at −30 degree C. Evaluation of the 7 channel SDD array and development of analog ASIC for its readout are also presented.

X-ray CCDs have superior spatial resolution of ~20μm and moderate energy resolution of ~130 eV(FWHM) at 5.9 keV. On the other hand, the number of pixels assigned to each readout node is generally so large that it takes several seconds to process a frame data of the entire chip. Relatively low pixel readout rate in order to keep readout noise low also limits the timing resolution of X-ray CCDs. Although a large number of readout nodes is essential to improve the timing resolution, size and power consumption of conventional readout circuits prevent us from being implemented in X-ray CCD camera systems onboard satellites. We are developing an application specific integrated circuits (ASIC) for multi readout of X-ray CCD signals. The ASIC with the size of 3mm×3mm has four channels of readout electronics that employs the delta-sigma (ΔΣ) digitization. The fabrication process is a 0.35μm complimentary metal-oxide semiconductor (CMOS) process provided by Taiwan Semiconductor Manufacturing Company (TSMC). The equivalent input noise was about 33μV and the power consumption was about 70mW per chip at the pixel rate of 44 kHz. When we used the X-ray CCD whose sensitivity was 3 μV/e-, the equivalent noise charge was 10.8e- and the energy resolution was 168 eV(FWHM) at 5.9 keV. The noise level of our ASIC is comparable to that of the conventional readout systems.

The radiation damage and recovery of polymethylmethacrylate (PMMA), Polystyrene PS and polycarbonate (PC) optical fiber under γ-ray irradiation was researched experimentally. The visible light transmission rate of the POF under different irradiation dose was measured. The results indicated that the radiation damage of three kinds of POF was wavelength-dependent. Under lower dose below 1000Gy, the transmission rate decreased identical in the whole visible light range. When the irradiation dose exceeded 5000Gy, the transmission rate reduced obviously, and the transmission rate indicated that the visible light transmission rate of the POF at the range of 400nm to 500nm comparing 600nm to 800nm, decreased seriously. The transmission rate of both PMMA and PC have an evident peak value in the range 550nm-650m, and that of PS has wide peak value at the range 500-700nm. In addition, we measured the recovery of three kinds of POF five times following irradiation at the wavelength 632nm. Under low dose irradiation 100 Gy, the transmission rate reduced a little, and the irradiation damage can recover during a short time. When the irradiation dose reached 1000 Gy, the recovery process need longer time. When the irradiation dose exceeded 5000 Gy, the transmission rate reduced obviously, and the recovery process is slow and the irradiation damage can't recover completely, that indicated fiber suffered lasting damage.

This paper evaluates the performance of a low noise, high throughput readout system for X-ray Charge Coupled Devices (CCDs). High pixel throughput (>0.5M pixels per second) can be achieved by two methods that are not mutually exclusive. Firstly, sections of the CCD image can be read out in parallel from multiple output nodes incorporated in modern CCDs. Pixel read times can also be reduced to the minimum value where the sampling circuitry can process pixel data at an acceptable noise level. To this end, two Application Specific Integrated Circuits (ASICs) were designed to process multiple video channels at high pixel rates. The ASIC presented in this paper employs a 4-channel Correlated Double Sampler (CDS) ASIC and is evaluated for noise performance and inter-channel crosstalk. Here we discuss the ASIC specification, design, application and measured performance.

The X-ray Imaging Spectrometers (XIS) on-board Suzaku is an X-ray CCD camera system that has features of low backgroud, good energy resolution, and high quantum efficiency (QE) at 0.2-12 keV band. However, an unexpected degradation of the QE at low energies (<1 keV) has emerged since November 2005. Some contaminants are considered to be adsorbed on the Optical Blocking Filter (OBF) for each sensor and cause the degradation. A suspected contamination source is rubber used in the shock absorber of the satellite gyro. For the recovery of the QE, we now design to remove the contaminants by increasing the OBF temperature. Before the on-board bakeout is performed, we need to confirm on the ground that it does not cause a serious damage to the OBF. In order to reproduce the on-board contamination, we adsorbed the contaminant of ~160 μg cm^-2 from the rubber on a spare OBF and a Thermoelectric Quartz Crystal Microbalance simultaneously, which are cooled down to -40°C. Although enexpected wrinkles appeared on the OBF surface during the adsorption and they remained through the subsequent bakeout, we could not find any tears on it. In addition, we estimated the desorption rate at -15°C to be ~5 μg cm^-2 per day. In our presentation, we also discuss the expected effect by the on-board bakeout based on these results.

The energy resolution of the X-ray CCDs onboard the Suzaku satellite (X-ray Imaging Spectrometer; XIS) has been degraded since the launch due to radiation damage. To recover from this, we have applied a spaced-row charge injection (SCI) technique to the Suzaku XIS in orbit. By injecting charge into CCD rows periodically, the energy resolution 14 months after launch is improved from 210 eV to 150 eV at 5.9 keV, which is close to the resolution just after the launch (140 eV). Additional information on these results is given in a companion paper by the XIS team. In this paper, we report the details of CCD charge transfer inefficiency (CTI) in the SCI mode, the correction method, and the implementation of it in ground analysis software for XIS data. In the SCI mode, CTI depends on the distance of a charge packet from the nearest charge-injected row, and the gain shows a periodic non-uniformity. Using flight data obtained with the onboard calibration sources, as well as a cosmic source (the Perseus cluster of galaxies), we studied the non-uniformity in detail. We developed a method to correct for the non-uniformity that will be valuable as the radiation damage progresses in future.

The CCD detectors in the X-ray Imaging Spectrometers (XIS) aboard Suzaku have been equipped with a precision charge injection capability. The purposes of this capability are to measure and reduce the detector degradation caused by charged particle radiation encountered on-orbit. Here we report the first results from routine operation of the XIS charge injection function. After 12 months' exposure of the XIS to the on-orbit charged particle environment, charge injection already provided measurable improvements in detector performance: the observed width of the 5.9 keV line from the onboard calibration source was reduced from 205 eV to less than 145 eV. The rate of degradation is also significantly smaller with charge injection, so its benefit will increase as the mission progresses. Measured at 5.9 keV, the radiation-induced rate of gain degradation is reduced by a factor of 4.3 ± 0.1 in the front-illuminated sensors when injecting charge greater than 6 keV equivalent per pixel. The corresponding rate of degradation in spectral resolution is reduced by a factor 6.5 ± 0.3. Injection of a smaller quantity of injected charge in the back-illuminated XIS sensor produces commensurately smaller improvement factors. Excellent uniformity of the injected charge pattern is essential to the effectiveness of charge injection in the XIS.

In the context of R&D studies financed by the Italian Space Agency (ASI), a feasibility study to evaluate the Italian Industry interest in medium-large scale production of enhanced CZT detectors has been performed by an Italian Consortium. The R&D investment aims at providing in-house source of high quality solid state spectrometers for Space Astrophysics applications. As a possible spin-off industrial applications to Gamma-ray devices for non-destructive inspections in medical, commercial and security fields have been considered by ASI. The short term programme mainly consists of developing proprietary procedures for 2-3" CZT crystals growth, including bonding and contact philosophy, and a newly designed low-power electronics readout chain. The prototype design and breadboarding is based on a fast signal AD conversion with the target in order to perform a new run for an already existing low-power (<0.7 mW/pixel) ASIC. The prototype also provides digital photon energy reconstruction with particular care for multiple events and polarimetry evaluations. Scientific requirement evaluations for Space Astrophysics Satellite applications have been carried out in parallel, targeted to contribute to the ESA Cosmic Vision 2015-2025 Announcement of Opportunity. Detailed accommodation studies are undergoing, as part of this programme, to size a "Large area arcsecond angular resolution Imager" for the Gamma Ray Imager satellite (Knödlseder et al., this conference).and a new Gamma-ray Wide Field Camera for the "EDGE" proposal (Piro et al., this conference). Finally, an extended market study for cost analysis evaluation in view of the foreseen massive detector production has been performed.

The success of the SWIFT/BAT and INTEGRAL missions has definitely opened a new window for follow-up and deep study of the transient gamma-ray sky. This now appears as the access key to important progresses in the area of cosmological research and deep understanding of the physics of compact objects. To detect in near real-time explosive events like Gamma-Ray bursts, thermonuclear flashes from Neutron Stars and other types of X-ray outbursts we have developed a concept for a wide-field gamma-ray coded mask instrument working in the range 8-200 keV, having a sensitivity of 0.4 ph cm⁻² s⁻¹ in 1 s (15-150 keV) and arcmin location accuracy over a sky region as wide as 3 sr. This scientific requirement can be achieved by means of two large area, high spatial resolution CZT detection planes made of arrays of relatively large (~ 1 cm²) crystals, which are in turn read out as matrices of smaller pixels. To achieve such a wide Field-Of-View the two units can be placed at the sides of a S/C platform serving a payload with a complex of powerful X-ray instruments, as designed for the EDGE mission. The two units will be equipped with powerful signal read out system and data handling electronics, providing accurate on-board reconstruction of the source positions for fast, autonomous target acquisition by the X-ray telescopes.

We study the gain variations in the HRC-I over the duration of the Chandra mission. We analyze calibration observations of AR Lac obtained yearly at the nominal aimpoint and at 20 offset locations on the detector. We show that the gain is declining, and that the time dependence of the gain can be modeled generally as a linear decrease in PHAs. We describe the spatial and temporal characteristics of the gain decline and discuss the creation of time-dependent gain correction maps. These maps are used to convert PHAs to PI channels, thereby removing spatial and temporal dependence, and allowing source pulse-height distributions to be compared directly regardless of observation date or location on the detector.

Microchannel plates have, because of their adaptability to various size and configuration formats, allowed a wide range of devices to be realized in astronomical applications for X-ray, UV and visible sensing, employing many different forms of readout techniques and photocathode types. Two essential performance issues are the quantum detection efficiency, and the uniformity of response over the detector field of view. In both of these areas microchannel plates have had issues, both in the consistency of high quantum detection efficiency, and in fixed pattern noise introduced by fabrication processes for microchannel plates. We show that recent work has improved the consistency of obtaining high quantum detection efficiency, and has virtually eliminated the causes of fixed pattern noise due to fabrication issues.

We review past and current attempts to measure X-ray polarization in celestial sources and describe research activity into a new family of materials which have been shown to exhibit linear dichroism at X-ray wavelengths. Such materials could add a polarimetry capability to the high energy resolution detectors proposed for future, high effective area, X-ray astrophysical observatories such as Constellation-X and XEUS. They have the potential to achieve useful minimum detectable polarization values for a number of sources in a sensible exposure time with XEUS.

Gamma-ray bursts are one of the most powerful explosions in the universe and have been detected out to distances of almost 13 billion light years. The exact origin of these energetic explosions is still unknown but the resulting huge release of energy is thought to create a highly relativistic jet of material and a power-law distribution of electrons. There are several theories describing the origin of the prompt GRB emission that currently cannot be distinguished. Measurements of the linear polarization would provide unique and important constraints on the mechanisms thought to drive these powerful explosions. We present the design of a sensitive, and extremely versatile gamma-ray burst polarimeter. The instrument is a photoelectric polarimeter based on a time-projection chamber. The photoelectric time-projection technique combines high sensitivity with broad band-pass and is potentially the most powerful method between 2 and 100 keV where the photoelectric effect is the dominant interaction process. We present measurements of polarized and unpolarized X-rays obtained with a prototype detector and describe the two mission concepts; the Gamma-Ray Burst Polarimeter (GRBP) for the U.S. Naval Academy satellite MidSTAR-2, and the Low Energy Polarimeter (LEP) onboard POET, a broadband polarimetry concept for a small explorer mission.

The development of micropixel gas detectors, capable to image tracks produced in a gas by photoelectrons, makes possible to perform polarimetry of X-ray celestial sources in the focus of grazing incidence X-ray telescopes. HXMT is a mission by the Chinese Space Agency aimed to survey the Hard X-ray Sky with Phoswich detectors, by exploitation of the direct demodulation technique. Since a fraction of the HXMT time will be spent on dedicated pointing of particular sources, it could host, with moderate additional resources a pair of X-ray telescopes, each with a photoelectric X-ray polarimeter in the focal plane. We present the design of the telescopes and the focal plane instrumentation and discuss the performance of this instrument to detect the degree and angle of linear polarization of some representative sources. Notwithstanding the limited resources the proposed instrument can represent a breakthrough in X-ray Polarimetry.

We devised and built a light, compact and transportable X-ray polarized source based on the Bragg diffraction at nearly 45 degrees. The source is composed by a crystal coupled to a small power X-ray tube. The angles of incidence are selected by means of two orthogonal capillary plates which, due to the small diameter holes (10 μm) allow good collimation with limited sizes. All the orders of diffraction defined by the crystal lattice spacing are polarized up to the maximum order limited by the X-ray tube voltage. Selecting suitably the crystal and the X-ray tube, either the line or the continuum emission can be diffracted, producing polarized photons at different energies. A very high degree of polarization and reasonable fluxes can be reached with a suitable choice of the capillary plates collimation. We present the source and test its performances with the production of nearly completely polarized radiation at 2.6, 5.2, 3.7 and 7.4 keV thanks to the employment of graphite and aluminum crystals, with copper and calcium X-ray tubes respectively. Triggered by the very compact design of the source, we also present a feasibility study for an on-board polarized source, coupled to a radioactive Fe⁵⁵ nuclide and a PVC thin film, for the calibration of the next generation space-borne X-ray polarimeters at 2.6 and 5.9 keV.

MAXI is the first payload to be attached on JEM-EF (Kibo exposed facility) of ISS. It provides an all sky X-ray image every ISS orbit. If MAXI scans the sky during one week, it could make a milli-Crab X-ray all sky map excluding bright region around the sun. Thus, MAXI does not only inform X-ray novae and transients rapidly to world astronomers if once they occur, but also observes long-term variability of Galactic and extra-Galactic X-ray sources. MAXI also provides an X-ray source catalogue at that time with diffuse cosmic X-ray background. MAXI consists of two kinds of detectors, position sensitive gas-proportional counters for 2-30 keV X-rays and CCD cameras for 0.5-10 keV X-rays. All instruments of MAXI are now in final phase of pre-launching tests of their flight modules. We are also carrying out performance tests for X-ray detectors and collimators. Data processing and analysis software including alert system on ground are being developed by mission team. In this paper we report an overview of final instruments of MAXI and capability of MAXI.

The Constellation-X mission, with 5 to 10 times the collecting area of any previous x-ray observatory, will obtain high-throughput, high resolution spectroscopic observations of x-ray sources ranging from super-massive black holes to the disks around young stars in the 0.25-4.0 keV region of the spectrum. We describe the need for high resolution X-ray spectroscopy on the Constellation-X mission, the various options for obtaining it, and the implementation that we recommend;, e.g. an off-plane grating system that can simultaneously provide spectral resolutions (λ/δλ) as high as 3000 and substantially increased throughput in the 0.2 to 2.0 keV region. As a flagship mission, Constellation-X will be a general purpose facility for the astronomy community. The reflection grating system we describe will enable Constellation-X to address the important questions of the next generation within NASA's current cost target.

The Lunar Orbital X-ray Fluorescence Imaging Spectrometer (LOXIA) designed and constructed at the Institute of High Energy Physics of the Chinese Academy of Sciences to perform chemical composition analysis of the Moon surface will operate on-board the Chang'E-1 mission, the first Chinese lunar spacecraft to be launched in 2007. We report the main results of the calibration measurements that we have performed using the X-ray beamline of the XACT facility of INAFOsservatorio Astronomico di Palermo G.S. Vaiana to determine the quantum efficiency of the XRS detector in the soft X-rays as a function of photon energy and angle of incidence.

The Italian small satellite mission AGILE has been launched the 23rd of April 2007. SuperAGILE is the solidstate hard X-ray imager of the mission. It is a coded-mask imager, with six arcmin angular resolution, a field of view in excess of 1 steradian, and a gross energy resolution. Ground calibration campaigns have been performed in the last year to optimize the detector response, for the energy calibration, to obtain the effective area at various angles for various energy bands, to study location accuracy and angular resolution. In this paper we report the preliminary results achieved. The AGILE satellite has just finished the first and larger part of its commissioning phase. SuperAGILE successfully passed the commissioning tests, and it is now in its final configuration. It is observing the X-ray sky since the end of June as a part of the Science Verification Phase. The in-flight calibrations has been started and will ended at the end of October. We show the first data obtained with the instrument in the first months of observations.

eROSITA (extended ROentgen Survey with an Imaging Telescope Array) will be one of three main instruments on the Russian new Spectrum-RG mission which is planned to be launched in 2011. The other two instruments are the wide field X-ray monitor Lobster (Leicester University, UK) and ART-XC (IKI, Russia), an X-ray telescope working at higher energies up to 30 keV. A fourth instrument, a micro-calorimeter built by a Dutch-Japanese-US collaboration is also in discussion. eROSITA is aiming primarily for the detection of 50-100 thousands Clusters of Galaxies up to redshifts z > 1 in order to study the large scale structure in the Universe and to test cosmological models including the Dark Energy. For the detection of clusters, a large effective area is needed at low energies (< 2 keV). Therefore, eROSITA consists of seven Wolter-I telescope modules. Each mirror module contains 54 Wolter-I shells with an outer diameter of 360 mm. In the focus of each mirror module, a framestore pn-CCD with a size of 3cm × 3cm provides a field of view of 1° in diameter. The mission scenario comprises a wide survey of the complete extragalactic area and a deep survey in the neighborhood of the galactic poles. Both are accomplished by an all-sky survey with an appropriate orientation of the rotation axis of the satellite in order to achieve the deepest exposures in the neighborhood of the galactic poles. A critical issue is the cooling of the cameras which need a working temperature of -80°C. This will be achieved passively by a system of two radiators connected to the cameras by variable conductance heat pipes.

We have been developing a hard X-ray polarimeter to open a new window for hard X-ray astronomy. The project is called as PHENEX (Polarimetry for High ENErgy X rays). The PHENEX detector is Compton scattering type polarimeter and it is constructed by several unit counters. The unit counter can achieve the modulation factor and the detection efficiency of 53% and 20% at 80 keV, respectively. Installing four unit counters, we have carried out balloon-borne experiment in Jun.13 2006 to preliminarily observe the polarization of the Crab Nebula in hard X-ray band. The PHENEX polarimeter successfully operated on the level flight and observed the Crab Nebula for about one hour. From the analysis of the obtained data, it was recognized that the PHENEX polarimeter does not make much spurious modulation and that the ratio of the signal from the Crab Nebula to the background from the blank sky is 1:3. Though we can not precisely determine the degree and the direction of the polarization for the Crab Nebula because of the trouble of the attitude control system, the obtained results were not inconsistent with those in the X-ray band. We will carry out balloon-borne experiment again, fixing the trouble of the attitude control system.